The prior art vehicle-used suction disk retainer is a box seat or a groove seat with a suction disk for being attaching to a glass or a smooth surface. Then object, such as a PDA is placed upon the suction disk. However the prior art has some defects, such as a complicated structure, a high molding cost and the assembly work is tedious. Thereby, the bad product ratio is high. The retainer cannot be attached on the surface for a long time. All these problems are necessary to be improved.